Re: No hash join across partitioned tables?

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От Tom Lane
Тема Re: No hash join across partitioned tables?
Дата
Msg-id 21238.1239980554@sss.pgh.pa.us
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Ответ на Re: No hash join across partitioned tables?  (Kris Jurka <books@ejurka.com>)
Ответы Re: No hash join across partitioned tables?  (Kris Jurka <books@ejurka.com>)
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Kris Jurka <books@ejurka.com> writes:
> So the default disable_cost isn't enough to push it to use the hash join
> plan and goes back to nestloop.  Since disable_cost hasn't been touched
> since January 2000, perhaps it's time to bump that up to match today's
> hardware and problem sizes?

I think disable_cost was originally set at a time when costs were
integers :-(.  Yeah, there's probably no reason not to throw another
zero or two on it.

Is there another issue here besides that one?  I think you were hoping
that the hash join would be faster than the alternatives, but the cost
estimate says it's a lot slower.  Is that actually the case?

            regards, tom lane

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